Atomizer wheel for simultaneously atomizing two components



Dec. 2, 1969 K. NIELSEN 3,481,546

ATOMIZER WHEEL FOR SIMULTANEOUSLY ATOMIZING TWO COMPONENTS Filed NOV. 29. 1957 3 Sheets-Sheet 1 INLET LIQUID 11 OR PlfJEl-R INLET LIQUID I INVENTOR kI-LT /EL.SE/V,

ATTORNEY H Go '5 52 0-1 Dec. 2, 1969 K. NIELSEQN 3,481,546

ATOMIZER WHEEL FOR SIMULTANEOUSLY ATOMIZING T WO COMPONENTS Filed Nov. 29, 196 3 Sheets-Sheet z Kl) J IWELSE/V ATTORNEYS Dec. 2, 1969 K. NIELSEN 3,

ATOMIZER WHEEL FOR SIMULTANEOUSLY ATOMIZING TWO COMPONENTS Filed Nov. 29, 19s? 3 S heets-Sheet s m :i \LIQUID L 3 k I8 FIG. 3

POWDER INLET INVENTOR 1m: mass/v ATTORNEYS United States Patent Int. Cl. l305b 3/10 US. Cl. 239-224 6 Claims ABSTRACT OF THE DISCLOSURE An atomizer wheel for simultaneously atomizing two components comprises two separate axially displaced supply spaces from which ejection channels lead to the circumference of the wheel, all of these channels terminating separately in the same plane normal to the axis of revolution. These channels are regularly distributed around the circumference.

The invention relates to an atomizer wheel for simultaneously atomizing two components, the said wheel comprising two separate supply spaces from which ejection channels lead to the circumference of the wheel.

Such atomizer wheels are often used in processes in which two different liquids are atomized into the same chamber. This is for instance the case in certain methods for producing milk powder, where the milk is first separated into cream and skimmed milk, whereupon these components are after a suitable regulation of their hydrogen ion concentration atomized into the same drying chamber separately, by which means the particles of the individual components are during the drying combined into whole milk-powder.

Another known method makes use of such atomizer wheels in the production of powders from two components, one of which is in the form of a dry or almost dry, generally fine-grained powder, while the other is in the form of a liquid. As an example of this may be mentioned the production of a dry product of sugar and milk, where a fine sugar-powder is atomized in the drying chamber simultaneously with the atomization of a concentrate of milk. As another example may be mentioned the reintroduction of the fine powder, which is carried along by the discharge air from the drying chamber and which, as a rule, cannot be mixed directly with the powder derived from the drying chamber without the latter powder acquiring undesirable propertiesfbut which by being atomized into the drying chamber simultaneously with the atomization of the liquid from which the powder is produced, can impart particularly satisfactory properties to the finished powder.

' In the known atomizer wheels, each of the two components is atomized at its individual level in the drying chamber, as the known atomizer wheels of this type may be regarded as being composed of two individual wheels placed one immediately on top of the other, so that the ejection channels from the two separate supply spaces are disposed at two diiferent levels.

This entail that the particles deriving from one of the two supply spaces in the drying chamber come into contact with the drying air before the particles from the two supply spaces are mixed with each other in the drying chamber and this can cause the particles of the former component to be influenced in a deleterious manner.

It is the object of the present invention to provide an atomizer wheel of the type referred to in which with a very great safety margin it is avoided that the particles of one component come into contact with the drying air before the particles of the two components have been mixed with each other.

According to the invention this is achieved by the ejection channels from the two supply spaces terminating substantially in the same normal plane regularly distributed around the circumference of the wheel.

By such a design of the atomizer wheel, the particles of the two components will be ejected at substantially the same level in the chamber, so that they will be thoroughly mixed with each other before coming into contact with the drying air.

When the two supply spaces are separated by a horizontal wall, it may, according to the invention, be expedient that the ejection channels lie at the level of one space, and that the ejection channels in communication with the other space are separated from the former space by means of thin dividing walls and are in communication with the latter space by means of oblique bores in the horizontal wall. In this way, the wheel becomes particularly simple to manufacture, in spite of the fact that the ejection channels from the two spaces disposed at diiferent levels are to lie at the same level.

In such an atomizer wheel, which is preferably intended for atomizing two components, one of which is a substantially dry powder, it may, furthermore, according to the invention, be expedient that the ejection channels are disposed at the level of the upper space in which one or more supply pipes have been inserted from above, preferably powder supply pipes, and that one or more supply pipes to the lower space have been carried from above down through the upper space and through an annular slot between the dividing wall of the two spaces and the hub of the wheel.

An expedient mounting of the supply pipes is achieved hereby and the fact that ejection is to take place at the level of the upper space presents no difficulties, the centrifugal force being fully sufficient to force the component supplied to the lower space upwards through the bores to the ejection channels.

It may, however, also according to the invention, be advantageous that the lower space is provided with a central aperture facing downwards and that below the latter a central supply pipe is mounted, while to the upper space one or more supply pipes have been led from above. By this means it becomes possible to manufacture the Wheel with a smaller diameter than would be the case with a simultaneous supply from above to the two spaces, viz. smaller by so much as corresponds to twice the width of the annular slot, which in the latter case is necessary for carrying the supply pipes down to the lower space.

In this case it is often advantageous that the ejection channels are disposed at the level of the lower space. When the supply pipes to the latter are led up from below, it must necessarily be partially open at the bottom, and it is therefore significant that the discharge resistance from the space through the channels is as slight as possible and this is achieved due to the fact that the extra resistance which would be encountered, if the material were to first pass through oblique bores to be led up to the level of the other space, is avoided.

In the latter case, it is, according to the invention, particularly expedient that the central supply pipe is a powder supply pipe. In this case, it will be the liquid component which is to pass through the oblique bores and this entails far less risk of the latter becoming obstructed even if they are made rather narrow, than if the powder is led through them.

In the following the invention will be further explained with reference to the drawing in which FIGURES l and 2 show an embodiment of the atomizer wheel acording to the invention viewed in axial section and in section on line IIII in FIG. 1 respectively, and

FIGURES 3 and 4 show another embodiment of the atomizer wheel according to the invention viewed in axial section and in section on line IVIV in FIG. 3.

The atomizer wheel shown in FIGURES l and 2 consists of a cylindrical, bowl-shaped part 1 with a hub 2 for securing the wheel on a shaft, not shown. The side wall of the bowl-shaped part 1 is approximately at its middle provided with a turned flange 3, pointing inwards, to which an annular dividing wall 4 is secured, which divides the interior of the bowl-shaped part into two spaces, 5 and 6.

In the upper edge of the bowl-shaped part 1 a number of ejection channels 7 and 8 have been provided so as to be regularly distributed around the circumference of the wheel, and these channels are closed in the upward direction by means of a cover ring 9. The channels 7 and 8 are disposed at the same level as the space 6, i.e., the upper space of the two spaces 5 and 6, and the channels 7 are in open communication with the space 6, while the channels 8 are blocked from this space by means of a dividing wall 10. The latter channels 8 on the other hand are in communication with the space 5 through bores 11 in the flange 3, which forms part of the dividing wall between the spaces 5 and 6.

The space 6 is bounded on the inside by a cylindrical member 12, which is mounted so as to be stationary coaxially with the atomizer wheel and projects downwards within the annular dividing wall 4. In this cylindrical member 12 a number of channels 13 have been designed, which terminate in the lower space 5 in the wheel and form supply pipes to this space. A supply pipe 14 to the space 6 projects slightly down into the latter from above beside the cylindrical member 12.

When the wheel is used for atomizing two different components, one component is led through the channels 13 to the space 5 and the other component is led through the supply pipe 14 to the space 6. The component led to the space 6 is ejected in an atomized state in the normal way from this space through the channels 7 due to the centrifugal force produced by the rotation of the wheel. The component supplied to the space 5 is first due to the centrifugal force being forced up through bores 11 to the channels 8, from where it is ejected in an atomized state at the same level as the former component. The two components are therefore mixed in the drying chamber in which the wheel is mounted, and the dry air led to this chamber will consequently not come into contact with one of the components before it has ben mixed with the other.

The two components may both be liquids, or one of them may be a completely or partially dry powder, preferably a fine-grained powder, e.g., the very fine powder that can be separated from the discharge air from the drying chamber. The channels 13 and the supply pipe 14 must in the normal Way be dimensioned in conformity with the material forming each of the two components. If the occasion should arise, more than a Single supply pipe 14 to the upper space 6 may be used. When one component is in the form of powder, it will, in the embodiment shown, be expedient that it is this component that is supplied to the upper space 6, which is in direct communication with the ejection channels 7.

The embodiment shown in FIGURES 3 and 4 is shown considerably more diagrammatically than the one shown in FIGURES 1 and 2. Also, in this case the wheel comprises two spaces, viz. the spaces 15 and 16 separated from each other by a dividing wall 17. Furthermore, there have, as is the case in FIGURES 1 and 2, been designed a number of ejection channels 18 and 19, but in this embodiment these channels are disposed at the level of the lower space 16, with which the channels 18 are in open communication, while the channels 19 are separated from said space by means of dividing walls 20 and are in communication with the upper space by means of bores 21.

One component to be atomized is supplied to space 15 through supply pipes or supply channels, which may e.g., be designed like the channels 13 in FIGURES 1 and 2, but are only shown purely diagrammatically as a supply pipe 22 in FIG. 3. The other component is supplied to the space 16 through a supply pipe 23, which is placed centrally below the space 16 and in the embodiment shown projects in through a central, circular opening 24 facing downwards in the lower wall of space 16, but the pipe 23 may, however, also terminate directly in this opening or slightly below same. When one of the two components is a substantially dry powder, the latter is preferably supplied to the space 16 through the pipe 23, while the other component is supplied to space 15 through pipe 22.

The form shown of the channels in the two embodi ments serves only as an example, as the form and dimensions of the ejection channels in each individual case must be chosen dependent on the given operational conditions in the same way as in the case of a conventional atomizer wheel. The number of the channels is correspondingly determined separately for each space, but it is necessary to determine the proportion between the number of channels leading to one space and the number of channels leading to the other space in such a way that they can be distributed uniformly around the circumference of the wheel so that it can become symmetrical around its axis of rotation, there being, as will be known, due to the frequently very high speed of rotation, required a very accurate balancing of the wheel.

What I claim is:

1. A rotatable atomizer wheel for simultaneously atomizing two substances, the said wheel comprising two separate axially displaced supply spaces respectively containing said substances from each of which spaces separate ejection channels lead to the circumference of the wheel, characterized in that the outlets of the ejection channels from the two supply spaces terminate separately substantially in the same plane normal to the axis of rotation regularly distributed around the circumference of the wheel.

2. An atomizer wheel as claimed in claim 1, where the two supply spaces are separated by a transverse wall, characterized in that all the ejection channel outlets are disposed at the level of one space and that the ejection channels in communication with the other space are separated from the one space by means of thin dividing walls and in communication with the other space by means of oblique bores in the horizontal wall.

3. An atomizer wheel as claimed in claim 2, preferably intended for atomizing two components, one of which is a substantially dry powder, characterized in that the two supply spaces comprise an upper and lower space and the ejection channels lie at the level of the upper space, into which there has from above been inserted at least one supply pipe, preferably a powder supply pipe, and that at least one supply pipe to the lower space is led from above down through the upper space and through an annular slot between the dividing Wall of the two spaces and the hub of the wheel.

4. An atomizer wheel as claimed in claim 2, preferably intended for atomizing two components, one of which is a substantially dry powder, characterized in that the two supply spaces comprise an upper and lower space and the lower space comprises a central opening which faces downwards, and that below the lower space a central supply pipe is mounted, while from above at least one supply pipe is led to the upper space.

5. An atomizer wheel as claimed in claim 4, characterized in that the ejection channels are disposed at the level of the lower space.

5 6. An atomizer wheel as claimed in claim 4, characterized in that the central supply pipe is a powder supply pipe.

References Cited UNITED STATES PATENTS WILBUR L.

6 FOREIGN PATENTS 3/ 1941 Germany. 2/ 1952 Great Britain. 7/ 1964 France.

BASCOMB, 111., Primary Examiner I. SOFER, Assistant Examiner US. Cl. X.R. 

